[Oilman72]

Posting this for a fly buddy. He recently purchased a R90. All went together well and he is a experienced builder. Twice now he has had the tail gear on end of tourque tube and the front one strip out in flight under no real hard maneveurs. Last time he flew one flight seemed all good. I showed up he was simply hovering and all of a sudden the tail let go. Took apart the tailcase and it appeared there were bubbles of sorts in the gear, meaning like airpocket in the plastic delrin material.
Here is the question: Is there a different set of gears you can get that are better? Is this that common of an issue with the R90 Gearing "Quality Control issies?" Is there a different unknown setup method not described in book to prolong those gears???

Any feedback on this matter would be appreciated. He is almost nervous to fly it, and I don't balme him at all .

[Charlie]

I've never had a problem with mine (yet), but I don't have a lot fuel through mine yet (about ten tanks). I have read about this happening but not very often, I hope it's not that common . Colin can probably answer your question better then me, he has lots of fuel burnt through his and I don't think he has had any problems (that I know of). He should be on here later, we'll see what he has to say.

[Colin]

Hi Oilman72,

I've had 5 sets of tail gears so far. I stripped one set when my collective servo stopped working in low tic-tocs and the tail grabbed the ground (resulting in a minor crash). I striped another set messing up a low stationary snake where the tail also grabbed the ground. Fortunately the heli lived for another day

I stripped one set in flight doing something stupid...I went full left tail rotor at 140% piro rate with my 601 (a blur) and then full right to stop it quickly (this would have happened with any helicopter). At 140% ATV it spins quick enough to pull the battery out of the tray if it's not strapped down good enough, so you can understand why they stripped.

I've never had a problem with stripping gears during even the most aggressive maneuvers.

Things to look for:
Set the mesh so you have minimal backlash but the gears still turn smoothly. Also, when installing the torque tube make sure the coupler is not shoved to far into the tail gear (on either end) as it will load the gear and push it forward tightening the mesh and causing the gears to burn up/strip out.

Colin

[bfarnden]

hey shawn thanks for posting this problem , i did go on line last night after this happened and there seemed to be a handfull of guys that have had this problem they are saying to boil the gears in water to make them not so brittle (myself i think they are crazy)i mean if thunder tiger wanted you to make the gears softer they would send you a pot and a bottle of evian in the kit.

i think i will chalk this one up as dumb luck that i recived a faulty gear and replace it , then fly the * out of it.

p.s. thanks to everyone who posted i appreciate the help.

[Colin]

I can assure you that there is not a common problem with the tail gears (unless you received a faulty set).

It’s a common mistake to put the torque tube end too far into the gear, which loads it ahead tightening the mesh. Make sure that when you put the tail gear box onto the boom that the torque tube is not pushed to far into the coupler. Also do the same for the front end….shove the boom in all the way and then pull it out about 1mm.

If you have already been doing this re check the mesh (with the gearbox fully tightened). The mesh will be different with the gearbox firmly bolted together compared loosely bolted together.

Hope this helps,

Colin

[G-copterbous-funk]

Apparently they are good enough for guys to transplant into Furys. Interesting read, you guys busting stuff might find it interesting also.

http://www.teambob00.com



Stephen

[Oilman72]

That looks so good it almost hurts my eyes!!!!